In a DVD reproduction apparatus, the digitized audio data read from a disc such as a CD (Compact Disc) and DVD (Digital Versatile Disc) is reproduced in a reproduction circuit, and an error correction is provided to the reproduced data in a correction circuit. The audio stream extracted from the data using reproduction and correction is supplied to an audio processing circuit.
When the audio stream is compressed coded data, the audio stream is decoded into PCM (Pulse Code Modulation) audio data in an audio processing circuit and then output to a postprocessing circuit through a selector. On the other hand, when the audio stream is PCM audio data, the audio stream itself is output to the postprocessing circuit through the selector. An example of the DVD reproduction apparatus is shown in U.S. Pat. No. 6,272,153.
At the output of the postprocessing circuit, one of the PCM audio data in which postprocessing such as virtual surround, pro logic, etc. has been performed or the PCM audio data supplied to the postprocessing circuit, is selected and output. The signal output from the postprocessing circuit is converted into an analog audio signal through a digital-to-analog conversion (DAC) circuit, amplified in an amplifying circuit and supplied to an audio speaker.
Furthermore, one of the audio stream or the output signal from the postprocessing circuit is selected and the selected output signal is converted in the IEC958 transceiver into a digital signal which conforms to the format IE060958 or IEC61987 which is a telecommunications standard of digitized audio data (hereinafter, IEC958 signal). The compressed coded data is output as the IEC958 signal from the IEC958 transceiver when the audio stream is selected, and the PCM audio data is output as the IEC958 signal from the IEC958 transceiver when the output data from the postprocessing circuit is selected.
In the case of the IEC958 signal, only two-channels of PCM data can be included in the IEC958 signal. For this reason, in the case of the PCM audio data of 5.1 multi-channels (L, R, C, Ls, Rs, and LFE) with which the postprocessing has been performed in the conventional DVD reproduction apparatus, only two-channels (L, R) can be included in the digitized audio data output from the IEC958 transceiver.
When an external DAC receives a digital output of an IEC958 signal with which the postprocessing has been performed and converts the signal into an analog audio signal, the elements (L, R) are provided, but the elements of Center (C), Left and Right rear surround (Ls, Rs), and Low Frequency Effect (LFE) are lost. Moreover, when an IEC958 signal with which the postprocessing has been performed is recorded by external equipment, only the digital audio signal including the elements (L, R) can be recorded and the elements of Center (C), Left and Right rear surround (Ls, Rs), and Low Frequency Effect (LFE) are lost.
Moreover, in the conventional DVD reproduction apparatus, when virtual surround processing is performed on the PCM audio data of an original sound in a postprocessing circuit, the digitized audio data signal output from the apparatus is a signal that has been subjected to the virtual surround processing. Therefore, when such a digital output signal is recorded by external equipment, the recorded signal is a signal that has been subjected to the virtual surround processing and is not the original sound.